In recent years, since ink-jet recording enables to form an image simply and less expensively, it has been applied to various printing fields such as photography, various types of printing, marking, and special printing such as color filters. Specifically, the performances of the ink-jet recording apparatus and the properties of the ink-jet ink have been markedly improved distinctly. Therefore, it has become possible to provide an ink-jet image of high quality comparable to an image produced by conventional silver halide photography.
However, in order to acquire an image of high quality, an expensive paper such as an exclusive recording medium paper is required. There is growing a need to achieve an image of high quality even by using non-expensive recording media such as a plain paper, a coated printing paper or a coated paper.
When image formation is tried onto a plain paper with an ink jet recording method, it is known that the following quality deterioration will be caused: strike-through (phenomenon in which an ink penetrate through to the wire side of paper), feathering (phenomenon in which an ink spreads in a cross direction along with fiber), a cockling (phenomenon in which a wrinkle is produced in a wave shape when paper absorbs the solvent in an ink), and curling of paper.
Moreover, when image formation is tried onto a coated printing paper with an ink-jet recording method, it is known that the following quality deterioration will be caused especially in the solid image portion which is produced by uniform image printing: mottling (phenomenon in which adjacent ink droplets are gathered and are fixed to result in producing irregular unevenness), bleeding (phenomenon in which ink droplets are mixed and a smear is produced in the boundary area of the image having a different color, it is also called “color bleeding”). These are phenomena caused by the poor ink absorptive property of the coated printing paper, and, for this reason, it is said that the coated printing paper is unsuitable as a recording medium of the ink-jet recording apparatus having a line head system capable for high-speed printing.
Moreover, in order to improve the above-mentioned print quality, ink-jet recording methods containing the step of applying a processing solution to a recording medium prior to image formation are described in the following Patent documents 1-4. Although the aggregation property of the ink is increased to result in improvement of image quality by applying the ink-jet recording methods containing the step using these processing solutions, there remain major problems that these methods will cause deterioration of glossiness or deterioration of cockling. Further, the ink-jet recording methods described in these documents have a problem of bleeding of the ejected ink.
Further, it is disclosed in the Patent document 5 that bleeding is improved by the way of printing while warming a recording medium using the ink-jet ink containing a resin neutralized with an amine.
Patent document 1: Japanese Patent Application Publication (JP-A) No. 06-092009
Patent document 2: JP-A No. 06-099576
Patent document 3: JP-A No. 07-001837
Patent document 4: JP-A No. 09-207424
Patent document 5: JP-A No. 2008-208153